vkGetPhysicalDeviceFragmentShadingRatesKHR

To query available shading rates, call:

VkResult vkGetPhysicalDeviceFragmentShadingRatesKHR(
    VkPhysicalDevice physicalDevice,
    uint32_t* pFragmentShadingRateCount,
    VkPhysicalDeviceFragmentShadingRateKHR* pFragmentShadingRates);

• physicalDevice is the handle to the physical device whose properties will be queried.
• pFragmentShadingRateCount is a pointer to an integer related to the number of fragment shading rates available or queried, as described below.
• pFragmentShadingRates is either NULL or a pointer to an array of VkPhysicalDeviceFragmentShadingRateKHR structures.

If pFragmentShadingRates is NULL, then the number of fragment shading rates available is returned in pFragmentShadingRateCount. Otherwise, pFragmentShadingRateCount must point to a variable set by the application to the number of elements in the pFragmentShadingRates array, and on return the variable is overwritten with the number of structures actually written to pFragmentShadingRates. If pFragmentShadingRateCount is less than the number of fragment shading rates available, at most pFragmentShadingRateCount structures will be written, and VK_INCOMPLETE will be returned instead of VK_SUCCESS, to indicate that not all the available fragment shading rates were returned.

The returned array of fragment shading rates must be ordered from largest fragmentSize.width value to smallest, and each set of fragment shading rates with the same fragmentSize.width value must be ordered from largest fragmentSize.height to smallest. Any two entries in the array must not have the same fragmentSize values.

For any entry in the array, the following rules also apply:

• The value of fragmentSize.width must be less than or equal to maxFragmentSize.width.
• The value of fragmentSize.width must be greater than or equal to 1.
• The value of fragmentSize.width must be a power-of-two.
• The value of fragmentSize.height must be less than or equal to maxFragmentSize.height.
• The value of fragmentSize.height must be greater than or equal to 1.
• The value of fragmentSize.height must be a power-of-two.
• The highest sample count in sampleCounts must be less than or equal to maxFragmentShadingRateRasterizationSamples.
• The product of fragmentSize.width, fragmentSize.height, and the highest sample count in sampleCounts must be less than or equal to maxFragmentShadingRateCoverageSamples.

Implementations must support at least the following shading rates:

If framebufferColorSampleCounts, includes VK_SAMPLE_COUNT_2_BIT, the required rates must also include VK_SAMPLE_COUNT_2_BIT.

The returned set of fragment shading rates must be returned in the native (rotated) coordinate system. For rasterization using render pass transform not equal to VK_SURFACE_TRANSFORM_IDENTITY_BIT_KHR, the application must transform the returned fragment shading rates into the current (unrotated) coordinate system to get the supported rates for that transform.